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Multi-Scale Modification of Metallic Implants With Pore Gradients, Polyelectrolytes and Their Indirect Monitoring In vivo
Published on: July 1, 2013
Tissue integration of growth factor-eluting layer-by-layer polyelectrolyte multilayer coated implants.
Mara L Macdonald1, Raymond E Samuel, Nisarg J Shah
1Harvard MIT Division of Health Sciences and Technology, Cambridge, MA, USA.
Biomaterials
|November 19, 2010
Summary
New Layer-by-Layer films deliver Bone Morphogenetic Protein 2 (BMP-2) for controlled bone healing. These coatings direct tissue response, enhancing medical device success and bone regeneration.
Area of Science:
- Biomaterials Science
- Tissue Engineering
- Regenerative Medicine
Background:
- Drug-eluting coatings can improve medical device outcomes by directing host tissue response.
- Biologic drugs, like growth factors, are crucial for directing tissue response but lack effective delivery strategies.
- Layer-by-Layer (LbL) polyelectrolyte multilayer films offer a promising platform for controlled biologic delivery due to their tunable properties and conformal coating capabilities.
Purpose of the Study:
- To develop and characterize LbL polyelectrolyte multilayer films for the controlled release of Bone Morphogenetic Protein 2 (BMP-2).
- To evaluate the in vitro and in vivo efficacy of BMP-2 released from LbL films in promoting bone formation.
Main Methods:
- Fabrication of LbL polyelectrolyte multilayer films incorporating microgram quantities of BMP-2.
- In vitro release studies of BMP-2 from LbL films over two weeks.
- Assessment of BMP-2 bioactivity in vitro using pre-osteoblast cell cultures (MC3T3 E1S4) and assays for alkaline phosphatase, calcium deposition (Alizarin Red), and matrix mineralization (Von Kossa).
- In vivo evaluation of BMP-2 LbL film-coated scaffolds implanted intramuscularly in rodents, assessing bone formation via MicroCT and histology from 4 to 9 weeks.
Main Results:
- LbL films successfully incorporated and released microgram quantities of BMP-2 over two weeks with minimal burst release (<1% in 3 hours).
- Released BMP-2 retained bioactivity, effectively inducing osteogenic differentiation in pre-osteoblasts.
- In vivo studies demonstrated that BMP-2 loaded LbL films promoted the differentiation of host progenitor cells into mature bone tissue at the implantation site.
Conclusions:
- LbL polyelectrolyte multilayer films provide a novel and effective platform for controlled delivery of BMP-2, enabling sustained release and potent osteogenic activity.
- These BMP-2 eluting LbL films represent a significant advancement in controlling host tissue response to medical implants.
- The technology holds potential for improving the success of implanted devices, offering new avenues for bone regeneration and wound healing, and paving the way for multi-therapeutic coatings.
